Delayed protection of HO-1 in the exercise preconditioning from the myocardial relative ischemic reperfusion injury

AIM:To explore the delayed protection of heme oxygenase-1 (HO-1) in the exercise preconditioning (EP) from the myocardial relative ischemia reperfusion injury (rI/R). METHODS:40 Wistar Rats were divided into 5 groups randomly:control group (CN), rI/R group (IR), EP+rI/R group (EI), HO-1 inductor hemin+rI/R group (HE) and HO-1 inhibitor ZnPP+EP+rI/R group (EZ). The following indexes were detected, including the HO-1activity in myocardium, the cardiac function parameter-pressure-rate product (heart rate × left ventricular developed pressure, PRP) and the content of MDA in coronary effluent. RESULTS:After myocardial rI/R, HO-1 activity increased significantly. Moreover, EP or HO-1 inductor could enhance this effect manifestly. Nevertheless, when the HO-1 inhibitor was administered before EP，HO-1 activity decreased. In addition, there was no distinct difference in the HO-1 activity between EI group and HE group. At the 30 min point of reperfusion, the PRP recovery rate of EI group was higher clearly than that of IR group. However, there was reverse effect between the EZ group and the EI group. The MDA in coronary effluent of EI group, EZ group and HE group were lower obviously than that of IR group and there was significant difference between EI group and EZ group. CONCLUSION:EP could protect the heart from the rI/R injury occurring 24 hours later, which might be performed through activating the HO-1.